NEW YORK — The latest blow to struggling J.C. Penney: One of its biggest shareholders confirmed that it’s sold more than 40 percent of its stake. Vornado Realty Trust’s move is perhaps the biggest indicator yet that investors are losing patience with a turnaround strategy that has failed to win over shoppers.

The stock has lost about two-thirds of its value in the past 12 months.

According to documents filed late Tuesday with the Securities and Exchange Commission, Vornado sold 10 million shares at $16.03 to Deutsche Bank on Monday. That price is 9 percent lower than Penney’s closing price of $17.69 on Friday.

Vornado, which owns and manages commercial real estate such as office buildings and malls, still holds 13.4 million shares, or 6.1 percent, of Penney’s stock. Vornado’s chairman and incoming CEO Steven Roth is a member of Plano, Texas-based Penney’s board.

Under the leadership of CEO Ron Johnson, who came on board in November 2011, the retailer scaled back most sales in favor of every day low prices. But shoppers looking for discount signs have fled, and Penney just finished a dismal year of mounting losses and steepening sales drops. Penney is now adding back some promotions, but analysts worry it won’t be able to stem sales declines fast enough to finance the company’s attempted transformation.

Johnson’s plan to revitalize the 1,100-store chain also includes installing shops featuring hip brands to replace racks of clothing.

The Wall Street Journal reported on Tuesday that some Penney’s board members are now considering selling the company or replacing Johnson if he can’t reverse the string of steepening sales drops. The report cited unidentified people who knew of the situation.

Penney has a steep road back. It lost $985 million in the year through Feb. 2, compared with a loss of $152 million the year before. Revenue fell nearly 25 percent to $12.98 billion.

Even Citi analyst Deborah Weinswig, one of the few on Wall Street who was still optimistic on Penney, is losing faith in Johnson’s ability to turn business around soon. She cut her rating on Penney shares to “Neutral” from “Buy” Wednesday and dropped her price target to $15, from $22. That suggests she expects shares to be more or less unchanged.

Weinswig said that after a trip to the company’s headquarters, she still supports Penney’s long-term strategy, which includes bringing in hipper designer brands such as Betsy Johnson. But she’s concerned that Penney’s pricing strategy has “yet to resonate” with shoppers, and worries that attempts to fix pricing and marketing won’t help sales recover fast enough

Penney has other worries aside from the steep sales drop. It is in a legal battle with rival Macy’s Inc. regarding its ability to sell Martha Stewart-brand products. It has already invested in her products, and if Penney loses, it could wind up with merchandise that it isn’t allowed to sell. Weinswig estimates that 30 percent of Penney’s home products were being designed by Martha Stewart.

J.C. Penney Co. stock fell 41 cents, or 2.7 percent, to $14.56 Wednesday afternoon. In the days after Johnson announced his vision for a new Penney in late January 2012, investors drove shares up 24 percent to $43. That gain has disappeared as investors lose confidence. Penney shares hit a 4-year low of $14.20 earlier Wednesday.